A day of peaceful commemoration of the second anniversary of Michael Brown’s death was marred Tuesday night when gunfire broke out after a protester was struck by a motorist.

After a quiet morning vigil and evening church service, the night turned violent when a car struck a protester standing on West Florissant Avenue.

Others among the roughly 75 protesters began trying to cut off the car, which then reversed direction to try to avoid the crowd, according to several witnesses.

At that point, witnesses said, several protesters pulled out guns and began chasing and firing at the fleeing car.

“I just started screaming, and the bullets started flying, and I started screaming some more,” said Heather DeMian, of St. Charles, a regular protester who has been live-streaming Ferguson protests.

It appears the driver did not intentionally strike the protester, according to Ferguson spokesman Jeff Small, who said the woman is being “very, very cooperative” with police.

"Investigators say the woman was simply driving down West Florissant at nighttime, unaware someone was standing in the street, until it was too late to stop before hitting them," Small said in a statement Wednesday morning.

He said there were bullet holes in the woman’s car, but no one in the vehicle was injured.

Police arrived at the scene within a minute, Small said. No arrests were made, and the extent of the injuries to the protester who was struck is unknown because the man was taken from the scene in a private vehicle, Small said.

Two people who were shaken up as the crowd fled the gunfire were taken to a hospital by ambulance.